greater dephosphorizing power. The first slag is known as puddle or mill cinder and is often used in the blast furnace. It is variable in composition, as shown in Table III-B.
TABLE III-B. Composition of Puddle or Mill Cinder.
"Where Made. Authority. Composition, per cent.
SiO, Fe P Mn 8
Harrisburg, Pa., ii it Troy, N. Y., Ironton, Ohio, Marietta, Ohio, Three English 'Works, " Boilings," Three English Works, " Tappings," Author. 11 ii a Trams. A.I.M. E., Vol. IX, p. 14,' Trans. A. X. M.S., Vol. IX, p. 14, Trans. A. r. Sf. E., Vol. IX, p. 14, J. and S. J., Journal, Vol. 1, 1891, p. 119^ J. and S. J.. Journal, Vol. 1, 1891, p. 119, 19.91 11.64 19.58 21.88 13.81 80.00 21.58 19.45 15.47 49.07 60.86 55.06 56.04 53.44 50.59 51.42 53.55 59.29 1.10 1.07 1.81 1.41 1.91 0.54 1.40 2.76 1.71 1.27 ....
' 8.62 ' 0.24
SBO. Hie.—Effect of work upon wrouglit-iron.—The influence of dilferent elements upon wrought-iron has never been fully discovered, owing to many disturbing conditions, foremost among which is the effect of varying amounts of work upon the finished material. This question arises in the case of steel, but is more important in wrought-iron, since the strength of the bar will depend upon the thoroughness with which the pieces forming the mass1 have been welded together. In Table III-C are given results oh-, tained at the Central Iron and Steel Works at Harrisburg, Pa., from plates rolled on their three-high train, and on a 25-inch universal mill. The better figures for the latter mill are due to the more complete development of fiber by the continuous rolling in one direction. The width 'was alike for similar thicknesses, and no difference was found in the universal plates whether they were 9 or 42 inches in width.
Usually there is a retrogression in quality as the size of the finished piece increases, and this is recognized in specifications.
SEC. Illf.—Heterogeneity. of wrought-iron.—The most complete investigation on the subject of wrought-iron is a report by